There is no joint filing in Canada.  As a resident of Canada, she will file a Canadian return.  She will report her marital status as married, and will report your net income.  She will use a Social insurance number of 000-000-000 for you and add your name and address as non-resident.  She does not report any of your income tax return details.  The net income figure is to enable the software to calculate her deductions correctly.

You can file a joint US return.